About 500,000 calves will be born on Irish farms in February and many farmers need to look at how they can improve their current facilities to help prevent incidences of scour and pneumonia.

For any calf shed we want to try to control moisture and air movement. There are a few different things farmers can do to assess their current housing facilities.

To assess air movement within a calf shed, crouch down at calf level in the pen and see if you can get a smell of ammonia, or think back to what the shed was like last year.

If you can get a smell then the air movement in the shed is not good enough, which in turn means bacteria and airborne contaminants are not getting away from the calf.

We also have to try to prevent draughts within sheds. If calves are lying randomly throughout a pen it is a good sign that there are no draughts at calf level. However, if they are avoiding certain areas it may require further inspection.

Warm environment

The lower critical temperature of a calf is the temperature below which an animal has to burn additional energy to keep warm. For calves less than three weeks of age, this is between 10°C and 15°C.

As calves grow, this lower critical temperature will decline, meaning they can more easily cope with lower temperatures.

Air speed can have a direct impact on this. With cold weather looking likely over parts of February, it is important that farmers take this into account for their calf-rearing protocol. Air movement of 0.2m/s is described as draught free while 0.3m/s can cause the calf to be chilled due to a draught.

We see in Table 1 that a newborn calf in a shed without a draught has a lower critical temperature of +9°C. However, if there is a draught of 2m/s (7.2km/h) then this critical temperature increases to 17°C.

If calves go below this lower critical temperature, they will be more stressed which makes them more likely to get pneumonia. Providing calves with a good deep bed of straw while protecting them from draughts will help them stay above their lower critical temperature.

Feeding levels should also be increased during periods of cold weather.

One option for large openings in sheds is to install a windbreaker. Where you are installing one that can stay fixed for the winter then it can be ratcheted into place. Clonmel Covers provide Easyfix windbreakers that can be made to suit a required size. A 1.2m high, 4.8m wide windbreaker costs approximately €200 excluding VAT. Easyfix windbreakers are available in sizes up to 4.8m by 4.8m, which cost €415 excluding VAT.

The void area of a windbreaker can vary, but they are generally 20% to 25% which will still ensure a good movement of controlled air, while preventing draughts.

Where farmers have calves in mono-pitch sheds with an open front then a fixed windbreaker may not be an option. There are a few different options that can be explored here, either a sliding windbreaker that would be pulled across between two stanchions, or a windbreaker on a roller. Cobra Ltd priced a sliding 4.8m wide, 3.5m high windbreaker at €325 excluding VAT.

The third option is to install a full windbreaker roller door.

This was installed on a calf shed in the North and while it is a more expensive option it does have the benefit of being easily opened and closed.

The doors were installed by Linton Solutions and cost approximately £1,100 (€1,247) per span of the shed.

Yorkshire boarding

The other options that more farmers are looking at installing to provide inlet ventilation for calf sheds are Yorkshire boarding and spaced boarding. Over the past year I have come across many cases where vented sheeting or solid sheeting has been removed and replaced with these types of cladding to provide better ventilation. There can be a massive variation in the void area of vented sheeting, 5% void all the way up to 18% void, which can mean a major difference in the amount of fresh air that enters a shed.

Spaced boarding is made up of a single line of boards with a gap no larger than 25mm between the boards. Different sized boards can mean a different void area. For example, a 100mm board and a 25mm gap will give a void area of 20%. If we want to increase ventilation still we can use a 75mm board and a 25mm gap; this gives us a void area of 25%. Spaced boarding may be useful on a sheltered side of the shed.

However, for more exposed sites then Yorkshire boarding should be used. It will still allow air to move through while preventing driving wind and rain from entering the shed. Yorkshire boarding is made up of two rows of vertical boards offset on either side of a purlin. Firstly the maximum gap that can be left between the two lines of boards is 50mm. If this is any larger, rain may be able to get through. The recommendation is to use a 150mm board and a 40mm gap. Using this design will still provide a 20% void area in your boarding.

To remove vented sheeting, supply and fit Yorkshire boarding is approximately €70/linear metre, for a 2m high section, as quoted by a builder. This would equate to a cost of €336/bay of a shed.

To remove vented sheeting, supply and fit spaced boarding costs approximately €50/linear metre, again for a 2m high section. This would equate to a cost of €240/bay of a shed.

Moisture

Reducing the moisture in pens should also be examined. The best way to do this is to ensure a good floor slope in pens with drains running along the front of pens.

Many sheds will have a flat floor which only holds the moisture and increases the amount of straw that is used. Moisture is also a breeding ground for bacteria and disease. An animal’s lower critical temperature will also be increased when they are wet.

Installing a floor slope with a 1:20 fall will help to bring moisture quickly to the front of the pen and away from calves. To remove the current concrete floor and replace with a 1:20 fall costs approximately €35-40/square metre. For a 4.8m by 4.8m pen this would cost approximately €864/pen.

It is important that the old pen is dug up for the front 1.5m at least to ensure the new concrete can be well binded in.

Fan and duct

A fan and a duct to ensure adequate ventilation on a still day is required for most calf sheds in Ireland. However, for an existing shed they may be a very cost-effective way of improving airflow. Magdek Thermal Systems supply custom tube systems for calf sheds with prices ranging from £1,000 to £1,500 depending on the size of the fan required.

For sheds with low roofs in particular it may be the only option to improve airflow. Running costs could be approximately £80-100/year (€90-113/year) depending how much it is used. However, where a fan and duct system is being used then calf jackets for the first few weeks of life may also be required to prevent chills.